1. Field
The following description relates to a photo detecting element, and more particularly, to a photo detecting element that has an improved gain adjustment structure, and an optical pick-up device that includes the photo detecting element.
2. Description of Related Art
A photo detecting element such as a photo detector integrated circuit (PDIC) may be used as an optical detector in an optical pick-up device. The PDIC may monitor optical power from an optical source such as a laser diode (LD). Typically, the PDIC further includes a photo diode (PD) and an amplifier. In an optical pick-up device for writing information to and/or reading information from a disc, the photo detecting element is a semiconductor element in which a plurality of parts are integrated so as to generate power calibration and monitor power for an auto power control of the LD that is incident to the disc.
Conventionally, to adjust a gain of the photo detecting element, the gain of an amplifier that is mounted to the photo detecting element is adjusted using an external resistor. Examples of the external resistor include a variable resistor and an array of a plurality of fixed resistors. However, in a gain adjustment structure in which an external resistor is a separate component from the photo detecting element, a size of the optical pick-up device increases and the manufacturing cost of the optical pick-up device also increases.